I'm trying to install Gentoo next to Windows 7 on a Samsung laptop, and I've gotten to the part where I should build the kernel. When I get to the part where it tells me to run 'emerge gentoo-sources', it runs, and then has the error 'Unable to remove module man pages' when installing dev-lang/perl-4.12.4-r1. Earlier on in the install, I am seeing errors like this:

Earlier in the install, there were some problems that seemed small, e.g. there was no /etc/portage/make.conf or /etc/portage/make.conf.example
I have no idea what is going wrong, so any suggestions would be great.

Hmm, getting out of the chroot and running umount /mnt/gentoo/ returns 'device is busy'.
EDIT: Oh, and I can remove those files by hand once the emerge fails.
EDIT2: I rebooted, and after remounting and chrooting, it all worked.

I wanted to change ubuntu to gentoo on my desktop long time ago and after ubuntu's been broken after update to 12.04 I have a good reason to do it.
Just today I had a similar issue with "unable to remove module man pages". The proble was in missing mount: